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1.
Sun hemp (Crotalaria juncea L.) residue as a proper nitrogen (N) source for a potato crop (Solanum tuberosum L.) was investigated. Leaf nutritional indices (LNI), i.e, SPAD (SPAD-502, Minolta, Japan), total chlorophyll (CHLT), and N-total content, and their validity to predict tuber yield and N recovery were estimated. Moreover, comparison with mineral N fertilization was conducted. The estimated variables exhibited linear increase patterns to sun hemp N rates. Moreover, correlation coefficients between LNI and yield components were significant. Comparison of sun hemp N-amounts with mineral nitrogen showed lower SPAD values, similar CHLT, N-total, and N recovery. However, the elevated application produced superior yields to mineral one. Sun hemp residue incorporation prior to potato accounted for adequate N supply. Additionally, LNI are appropriate tools to determine potato N status and enable yield prognoses.  相似文献   

2.
We compared trapping of Rhizobiumleguminosarum biovar trifolii isolates under field soil and non-soil environmental conditions. Isolates were obtained from white clover (Trifoliumrepens L.) and red clover (T. pratense L.) grown directly in the field and from plants inoculated with soil from the same site using a plant infection technique. Isolates were identified by genomic polymerase chain reaction (PCR) fingerprinting using primers derived from the enterobacterial repetitive intergenic consensus (ERIC) sequences. The isolates trapped from soil dilutions in the laboratory included a number of major ERIC types that were not found in the field trapped nodules, suggesting that sampling of clover Rhizobium strains from soil dilutions may not be representative of the field nodulating population.  相似文献   

3.
Enumeration of Rhizobium in soil is usually accomplished by the most probable number (MPN) plant infection method. The accuracy of MPN counts as compared to plate counts was determined for five strains of cowpea rhizobia. Host plants included cowpea (Vigna unguiculata (L.) Walp.), siratro (Macroptilium atropurpureum (DC.) Urb.) and peanut (Arachis hypogaea L.). Plastic growth pouches were used primarily for cowpea and siratro while plastic cups containing vermiculite were used for peanut. The number of rhizobia determined by the MPN method using cowpea, siratro and peanut underestimated the population from 10- to 100-fold. A control experiment using soybeans (Glycine max (L.) Merrill) indicated that the MPN method was accurate for R. japonicum. Experimentors using the MPN method should be aware of its accuracy for particular Rhizobiutn-legume combinations.  相似文献   

4.
Summary An attempt has been made to estimate quantitatively the amount of N fixed by legume and transferred to the cereal in association in intercropping systems of wheat (Triticum aestivum L.) — gram (Cicer arietinum L.) and maize (Zea mays L.) —cowpea (Vigna unguiculate L.) by labelling soil and fertilizer nitrogen with 15N. The intercropped legumes have been found to fix significantly higher amounts of N as compared with legumes in sole cropping if the intercropped cereal-legume received the same dose of fertilizer N as the sole cereal crop. But when half of the dose of the fertilizer N applied to sole cereal crop was received by intercropped plants, the amount of N fixed by legumes in association with cereals was significantly less than that fixed by sole legumes. Under field conditions 28% of the total N uptake by maize (21.2 kg N ha–1) was of atmospheric origin and was obtained by transfer of fixed N by cowpea grown in association with maize. Under greenhouse conditions gram and summer and monsoon season cowpea have been found to contribute 14%–20%, 16% and 32% of the total N uptake by associated wheat and summer and monsoon maize crops, respectively. Inoculation of cowpea seeds with Rhizobium increased both the amount of N fixed by cowpea and transferred to maize in intercropping system.  相似文献   

5.
Five chick pea (Cicer arietinum L.) varieties when inoculated with an effective Rhizobium strain showed significant variations in nodule number. The root exudates of the plant varieties were analysed for sugars, TCA cycle intermediates and amino acids. Xylose, citrate, alanine and phenylalanine were detected in exudates of one or two varieties, in addition to compounds common to all varieties such as glucose, glucosamine, ribose, serine, homoserine and glutamic acid. However, the concentration of all these compounds in the exudates collectively was inadequate to support Rhizobium growth under aseptic conditions. Several of the exuded compounds were chemotactic at very low concentrations. The rhizobia showed taxes toward growing roots of all the varieties in agar plates. Competition experiments showed that the rhizobia have a multiple-chemotactic system like that of Escherichia coli. It appears that root exudates accumulate Rhizobium along the growing roots through chemotaxis. The minor differences in exudate composition among varieties is not a factor responsible for variation in nodule number.  相似文献   

6.
The present study was designed with the objective of improving the nodulation and growth of chickpea (Cicer arietinum L.) by integrating co-inoculation of Rhizobium sp. (Mesorhizobium ciceri) and plant growth promoting rhizobacteria (PGPR) carrying ACC (1-aminocyclopropane-1-carboxylate) deaminase activity with P-enriched compost (PEC) under irrigated and rainfed farming systems. PEC was prepared from fruit and vegetable waste and enriched with single super phosphate. The results demonstrated that co-inoculation significantly (P?<?0.05) increased the number of nodules per plant, nodule dry weight, pods per plant, grain yield, protein content, and total chlorophyll content under irrigated and rainfed conditions compared to inoculation with rhizobium alone. Integrating PEC with co-inoculation showed an additive effect on the nodulation and growth of chickpea under both farming systems. Analysis of leaves showed a significantly (P?<?0.05) higher photosynthetic rate and transpiration rate in comparison with inoculation with Rhizobium. Compared to irrigated farming system, co-inoculation with PEC under rainfed conditions was more beneficial in improving growth and nodulation of chickpea. Post-harvest soil analysis revealed that the integrated use of bioresources and compost enhanced microbial biomass C, available N content, dehydrogenase, and phosphomonoesterase activities.  相似文献   

7.
The effect of soil sterilization, and seed inoculation with three Rhizobium strains (3889, CP5b and IC 26) were studied on 5 chickpea (Cicer arietinum L.) genotypes (Jordan local, ILC 72 from Spain, ILC 484 from Turkey, C 235 from India, and ILC 1272 from U.S.A.). The main objective of the work was to investigate the effect of inoculation with different Rhizobium strains on yield, nodulation and other agronomic characteristics of different chickpea genotypes. Inoculation with Rhizobium resulted in a significant increase in grain yield for all genotypes tested. The average increase due to inoculation was 110% over the uninoculated control. Inoculation resulted in more nodules, greater nodule fresh weight and higher nitrogen uptake. The various Rhizobium strains differed in their effects. Genotypes responded differently to inoculation.  相似文献   

8.
Compressive behaviour of hemp (Cannabis Sativ L.) stems is important for the design of hemp handling and processing machines. Experiments were carried out to measure the compressive properties of stems from two hemp varieties: Alyssa (grown for fibre only) and Petera (grown for both fibre and seed), produced in Manitoba, Canada. The physical properties of the hemp specimens were measured. For each variety, an air-dried hemp stem was divided into three height sections along the stem: upper, middle and lower. For each section, the hemp stem was further cut into 25.4 mm long specimens. Individual specimens were compressed in the axial and lateral directions using a universal testing machine. The load-displacement curves were recorded, and compressive properties were derived from the load-displacement curves. The outer diameter of the hollow hemp specimens varied from 6 to 17 mm; the linear density varied from 10 to 37 g m−1. Diameter and linear density were greater for Petera than Alyssa, and at the lower height section than the higher section for both varieties. The compression tests showed that the maximum compressive load varied from 58 to 1425 N, and the energy requirement varied from 23 to 1809 mJ, depending on the variety, height section and diameter of stem, and compression direction. In general, the maximum compressive load and the energy requirement were greater in the lower section and for larger diameters; higher loads and energy were observed for Petera than for Alyssa and for the axial compression direction than for the lateral direction.  相似文献   

9.
Nitrogen (N) fixation by legume-Rhizobium symbiosis is important to agricultural productivity and is therefore of great economic interest. Growing evidence indicates that soil beneficial bacteria can positively affect symbiotic performance of rhizobia. The effect of co-inoculation with plant growth-promoting rhizobacteria (PGPR) and Rhizobium, on nodulation, nitrogen fixation, and yield of common bean (Phaseolus vulgaris L.) cultivars was investigated in two consecutive years under field conditions. The PGPR strains Pseudomonas fluorescens P-93 and Azospirillum lipoferum S-21 as well as two highly effective Rhizobium strains were used in this study. Common bean seeds of three cultivars were inoculated with Rhizobium singly or in a combination with PGPR to evaluate their effect on nodulation and nitrogen fixation. A significant variation of plant growth in response to inoculation with Rhizobium strains was observed. Treatment with PGPR significantly increased nodule number and dry weight, shoot dry weight, amount of nitrogen fixed as well as seed yield and protein content. Co-inoculation with Rhizobium and PGPR demonstrated a significant increase in the proportion of nitrogen derived from atmosphere. These results indicate that PGPR strains have potential to enhance the symbiotic potential of rhizobia.  相似文献   

10.
Plant‐growth promoting rhizobacteria (PGPR), in conjuction with efficient Rhizobium, can affect the growth and nitrogen fixation in pigeonpea by inducing the occupancy of introduced Rhizobium in the nodules of the legume. This study assessed the effect of different plant‐growth promoting rhizobacteria (Azotobacter chroococcum , Azospirillum brasilense, Pseudomonas fluorescens, Pseudomonas putida and Bacillus cereus) on pigeonpea (Cajanus cajan (L) Milsp.) cv. P‐921 inoculated with Rhizobium sp. (AR‐2–2 k). A glasshouse experiment was carried out with a sandy‐loam soil in which the seeds were treated with Rhizobium alone or in combination with several PGPR isolates. It was monitored on the basis of nodulation, N2 fixation, shoot biomass, total N content in shoot and legume grain yield. The competitive ability of the introduced Rhizobium strain was assessed by calculating nodule occupancy. The PGPR isolates used did not antagonize the introduced Rhizobium strain and the dual inoculation with either Pseudomonas putida, P. fluorescens or Bacillus cereus resulted in a significant increase in plant growth, nodulation and enzyme activity over Rhizobium‐inoculated and uninoculated control plants. The nodule occupancy of the introduced Rhizobium strain increased from 50% (with Rhizobium alone) to 85% in the presence of Pseudomonas putida. This study enabled us to select an ideal combination of efficient Rhizobium strain and PGPR for pigeonpea grown in the semiarid tropics.  相似文献   

11.
Polyphasic characterization of 54 indigenous mung bean (Vigna radiata L.) rhizobia from different geographic regions of China was determined by analyzing the variability of 16S rRNA gene RFLP, 16S–23S rRNA gene Intergenetic Spacer (IGS) RFLP, G-C rich RAPD and phenotype assays. Based on these characteristics, mung bean rhizobia were clustered into four groups. Group I comprised 16 slow-growing isolates from a variety of geographic regions. This group was genetically distinct from Bradyrhizobium japonicum and Bradyrhizobium liaoningense, and may represent a new species. Group II was composed of 18 isolates, which could be sub-divided into two sub-groups that were respectively related to B. japonicum and B. liaoningense. Group III comprised 12 isolates from South China and clustered together with Bradyrhizobium elkanii. Group IV formed a miscellany of 8 fast-growing isolates variously related to the genera Sinorhizobium, Rhizobium and Mesorhizobium.  相似文献   

12.
Changes in the populations of Rhizobium strains CB756str, CB985 and CB1024strspc in the rhizospheres of cowpea (Vigna unguiculata) and black gram (V. mungo) grown at three sites were evaluated. The population dynamics of the three rhizobia varied with soil type but the strain responses on the two legumes were generally similar. Most noticeable was the ability of CB756str to grow in the sandy soil (Beerwah) but not in the heavy clays (Narayen and Emerald). In contrast, the levels of CB1024strspc and CB985 generally increased in the clay soils.Nodulation (% due to the inoculum strain) did not always reflect events within the rhizosphere. Although not suited to Narayen, CB756str formed a similar proportion of the nodule population of black gram as CB1024strspc but this may have been due to higher seed inoculum levels of CB756str. At Emerald nodulation by all three strains of rhizobia was poor regardless of the success in colonization of the rhizosphere. Successful competition for nodule sites by native rhizobia may contribute to this discrepancy between Narayen and Emerald although lower seed inoculum levels at Emerald may also have been important.Nodule decay was consistently associated with a large increase in the number of rhizobia per root system. This is likely to be important in the survival of strains into the following season.Comparisons of nodulation by parent and mutant rhizobia suggested that resistance to antibotics may have slightly reduced nodule forming ability for CB1024strspc on black gram at Emerald.  相似文献   

13.
Abstract

Rhizobia were screened in growth chamber and greenhouse tests with the host plants: bean (Phaseolus vulgaris L.), lentil (Lens esculenta Moench.), cowpea (Vigna unguiculata (L.) Walp) and peanut (Arachis hypogaea L.). Rhizobial isolates varied in effectiveness, time to nodulation, and host plant specifities. Initial screening procedures in plastic growth pouches allowed selection of infective strains of Rhizobium. These tests enabled the selection of a small number of highly effective isolates for more critical evaluation. Highly significant correlations (p=0.01) were obtained between shoot dry weight and total nitrogen, suggesting that the technique was applying sufficient selection pressure to differentiate variation in N2 fixation among strains of Rhizobium. Results indicate that highly effective rhizobia can be efficiently selected under controlled conditions following a step‐wise procedure.  相似文献   

14.
ABSTRACT

The effects of plant age at the time of mowing on sunn hemp (Crotalaria juncea L.) tissue decomposition, nitrogen (N) release, and fiber content in Krome very gravelly loam were assessed. Combined leaf and stem tissue from 42-, 77- or 112-day-old sunn hemp plants was placed in mesh bags and buried below the soil surface in the field. Bags were removed bi-weekly and dry weights, N concentration, acid detergent fiber (ADF) and neutral detergent fiber (NDF) concentrations in buried sunn hemp tissues were determined. There was a rapid decrease plant tissue dry weight during the first 14 days after tissue was buried, followed by a slow gradual decrease. The amount N per hectare was much lower for 42-day-old than 112-day-old sunn hemp. Tissue of the youngest plants decomposed the quickest. Forty two-day-old tissue had a higher N concentration, N mineralization rate, and lower NDF and ADF than 77- or 112-day-old tissue. Mowing and soil incorporation of a 42-day-old instead of a 77- to 112-day-old sunn hemp cover crop prior to planting a cash crop can be beneficial for a fast-growing cash crop planted soon after soil incorporation of the cover crop.  相似文献   

15.
Two-year rice (Oryza sativa L.)-based crop rotation of “maize (Zea mays L.) relay cropped by horse gram (Dolichos biflorus L.) in the first year followed by upland rice in the second year”, was reported earlier to increase phosphorus (P) uptake by rice through enhancing native arbuscular mycorrhizal (AM) activities. This crop rotation was compared with three other rice-based crop rotations practiced by the upland rice farmers of eastern India for AM-mediated P acquisition of upland rice through on-farm experiment in farmers' participatory mode during wet seasons of 2004, 2005, 2006, and 2007 in fixed plots. The farmers' rotations included (1) green gram (Phaseolus aureus) in first year followed by upland rice in second year; (2) black gram (Phaseolus mungo) in first year followed by upland rice in second year; and (3) radish (Raphanus sativus) in first year followed by upland rice in second year. “Maize–horse gram/rice” rotation encouraged maximum native AM fungal colonization (10.4–38.8%) and P uptake (2.2–2.6 mg P/g plant) by rice over other three farmers' rotations tested. Rice grain yield was also highest (2.25–2.35 t/ha) in the maize–horse gram/rice rotation.  相似文献   

16.
An experiment was conducted to study the effect of inoculation of Rhizobium suspension in Albizia procera (Roxb.) Benth, Albizia lebbeck (L.) Benth, and Leucaena leucocephala (Lam.) De Wit. seedlings grown in sterilized and non‐sterilized soil media. Control treatments were maintained by non‐inoculation. Inoculation response was observed strong in sterilized and modest in non‐sterilized soil when compared to respective control treatments. Increase in height was found 105.07%, 63.42%, and 109% higher in sterilized soil and 52.1%, 68.6%, and 95.8% in non‐sterilized soil for Albizia procera, Albizia lebbeck, and Leucaena leucocephala, respectively, after a period of 4 months. Nodule number increased up to 10.27 and 3.51 times in Albizia procera, 11.47 and 4.3 times in Albizia lebbeck, and 7.22 and 2.9 times in Leucaena leucocephala due to inoculation in sterilized and non‐sterilized soil media respectively. Significant increase in nodule dry weight and nitrogenase activity was also recorded in both sterilized and non‐sterilized soil for all the species tested. Nitrogenase activity per plant per hour was recorded 68.75,11.58, and 13 times higher in sterilized and 6.7,5.53, and 3.38 times higher in non‐sterilized soil over control for the species respectively after 4 months. In the tree species tested the inoculation of Rhizobium showed higher productivity, modulation and nitrogenase activity than control suggesting the idea that application of Rhizobium suspension greatly enhances plant growth, modulation, and nitrogenase activity.  相似文献   

17.
《Journal of plant nutrition》2013,36(12):2391-2401
Abstract

Availability of phosphorus (P) in soil and its acquisition by plants is affected by the release of high and low molecular weight root exudates. A study was carried out to ascertain the qualitative and quantitative differences in root exudation among the genotypes of maize (Zea mays L.) and green gram (Vigna radiata L.) under P‐stress. Results showed that both inter‐ and intra‐species differences do exist among maize and green gram in terms of root exudation, P uptake, and shoot and root P content. In general, green gram, a legume crop, had greater root exudation compared to maize. However, the amino acid content of the total root exudates in maize was two‐fold as compared to green gram. The maize and green gram genotypes possessed genetic variability in root exudation. Irrespective of the species or genotypes, a positive relationship was found among P uptake rates, total root exudation, and shoot and root 32P content. The amount of sugars and amino acid present in the root exudates of P‐starved seedlings also add to the variation in P uptake efficiency of genotypes.  相似文献   

18.
Three species of AM fungi, Glomus mosseae, Glomus microcarpum, Gigaspora margarita and a fungus that mimics the properties of AM fungi, Piriformospora indica, were tested on green gram [Phaseolus aureus Roxb. (= Vigna radiata var. radiata)] individually and in combination with Rhizobium for their influence on growth and seed yield. The growth parameters analyzed were dry biomass, total leaf area, total chlorophyll,% root colonization, nodulation, and nitrogen, phosphorus, and potassium (NPK) content of leaf tissues using standard methodologies. Glomus microcarpum was found to be more effective in promoting biomass and seed yield when applied alone. But in combination with Rhizobium, G. mosseae enabled highest production of biomass. The tissue nitrogen content was high in G. microcarpum—Rhizobium dual inoculated plants. Many other characteristics were high in dual inoculation, while tissue P was high in individual treatment of G. mosseae. Piriformospora indica was not found to be a good synergist on green gram.  相似文献   

19.
Although Phaseolus vulgaris L. is native from the Americas and is currently cultured in diverse areas, very little is known about the diversity of symbiotic nitrogen fixing Rhizobium (mycrosymbiont) in many of those cultures. Therefore, the aim of this study was to assess the genetic diversity of Rhizobium present in nodules of P. vulgaris in the central region of Chile. A method to extract DNA from surface-sterilized nodules was applied to two populations of the same seed variety grown in different fields. The 16S rRNA and nifH genes were amplified directly from the DNA extracted. DGGE analysis and clone libraries showed a restricted genetic diversity of the microsymbiotic populations that nodulate P. vulgaris. Both molecular markers revealed the presence of a microsymbiont closely related to Rhizobium etli in all the plants from the soils studied, indicating that the populations of Rhizobium sp. nodulating P. vulgaris in the central region of Chile displayed an extremely low genetic diversity. The level of genetic diversity in microsymbiont populations in plants grown in soils with different origin suggested that other factors rather than the indigenous soil rhizobial populations play a major role in the selection of the symbiotic partner in P. vulgaris.  相似文献   

20.
菌剂与肥料配施对矿区复垦土壤白三叶草生长的影响   总被引：2，自引：0，他引：2  
采用盆栽试验研究了矿区复垦土壤菌剂与肥料的不同配施对白三叶草(Trifolium repens Linn)生长的影响。结果表明: 双接种VA 菌根真菌(Glomus mossea)和根瘤菌(Rhizobium)能显著提高白三叶草根瘤数、根瘤鲜重和固氮酶活性, 根瘤数在有机肥双接种与无机肥双接种处理之间差异不显著, 而根瘤鲜重和固氮酶活性差异显著; 肥料与各菌剂组合处理中, 有机肥双接种处理的白三叶草分枝数、干物质重最大; 在白三叶草生长40 d 和150 d 时, 双接种处理的叶片数均为各处理中最大值; 接种VA 菌根真菌、根瘤菌和双接种均可增加白三叶草根系的菌根侵染率和土壤孢子数, 总体表现为双接种处理＞接种VA 菌根真菌＞接种根瘤菌, 有机肥相应处理＞无机肥相应处理＞对照; 肥料与菌剂的配合施用可有效提高植物对土壤氮、磷、钾养分的吸收。在矿区复垦土壤上有机肥与VA 菌根真菌和根瘤菌菌剂配施能显著促进白三叶草的生长, 是提高矿区复垦土壤植被恢复中比较适宜的组合方式。  相似文献   

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